Summary/Abstract Chemicals such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and triclosan alter cellular Ca2+ signaling acting through L-type voltage-sensitive Ca2+ channels (CaV1) and/or ryanodine receptors (RyR), which regulate the entry of Ca2+ from external sources or the release of Ca2+ from internal stores, respectively. These channels alone are central to the function of a vast number of cellular signaling processes and chemical disruption of these targets is correlated with altered dendritic growth, altered neuromuscular health, and altered learning and memory in exposed model organisms. The list of toxicants, and their receptor targets, that lead to such Ca2+ signaling disruption (CSD; used for disruption and disrupting) is currently unknown. However, based on structural similarities to known CSD compounds, we hypothesize that a large number of chemicals currently in use or in the environment are capable of CSD representing a need for high-throughput tools able to screen individual chemicals and complex environmental mixtures. Recent work has identified the downstream regulatory element antagonistic modulator (DREAM) which is the only Ca2+ sensor identified to date that binds speci?cally to DNA and regulates transcription in a Ca2+-dependent manner. Thus the DREAM protein acts as a direct connection between changes in intracellular Ca2+- and gene transcription Our preliminary work demonstrates that select CSD compounds can alter DREAM mediated transcription in model cell lines representing a unique opportunity to establish a CSD screening assay. Here, we take a multi-tiered approach to extend our understanding of DREAM, in-light-of pollutant responses, by screening known and predicted CSD chemicals for their ability to drive DREAM transcription in luciferase transfected cell lines and evaluating the extent of DREAM mediated transcription or altered phenotypes in CSD exposed wildtype and DREAM knockout zebrafish. The proposed work will establish gene transcription as a toxic outcome due to CSD and lead to the development and validation of important cellular and animal tools able to cost and time effectively evaluate large numbers of compounds for CSD activity. This work has vast implications on the health of exposed organisms as DREAM is known to contribute to such processes as learning and memory, pain reception and endocrine signaling in the hypothalamus, pituitary and the thyroid gland and has been associated with Huntington?s disease, a myotrophic lateral sclerosis and type II diabetes. Understanding the role of CSD in these physiological and pathophysiological states would aid in pollutant associated risk assessment.